Automatic engine stopping and starting for a parked vehicle

ABSTRACT

Systems and methods for operating an engine that may be automatically stopped and started responsive to vehicle operating conditions are disclosed. In one example, the engine may be automatically started after it has been automatically stopped in response to a driver applying a brake pedal while the vehicle&#39;s transmission is engaged in park. The engine may be started to increase transmission pump pressure prior to engaging a gear to reduce vehicle launch time.

FIELD

The present description relates to systems and method for automaticallystarting an engine of a vehicle that has been stopped with the vehicle'stransmission engaged in park. The system and methods may improvelaunching of the vehicle after the vehicle is disengaged from park.

BACKGROUND AND SUMMARY

An engine of a vehicle may be automatically stopped via a controller inresponse to vehicle operating conditions. For example, the engine may bestopped without the vehicle's driver specifically requesting an enginestop via an input that is dedicated to engine stopping and starting. Theengine may be stopped to conserve fuel while the vehicle's driver (e.g.,human or autonomous) waits for traffic conditions to clear or until thedriver is ready to leave the vehicle's present location. The engine maybe stopped while the vehicle's transmission is engaged in a gear, inneutral, or in park. If the vehicle is in a gear while the engine isstopped, the vehicle may be held in the gear by supplying hydraulicpressure to the transmission gear clutches via an electric pump.Similarly, at least some of the transmission's gear clutches may beengaged if the transmission is in neutral. By keeping one or more gearclutches engaged while the engine is stopped, engine torque may betransferred to the vehicle's wheels sooner after an engine restartbecause less fluid may have to be supplied to the transmission clutches.However, if the transmission is engaged in park, all gear clutches mayhave to be released. Consequently, if the engine is automaticallyrestarted, significantly more transmission fluid may have to bedelivered to the gear clutches before engine torque may be transferredto the vehicle's wheels. Having to supply larger amounts of fluid toengage transmission gear clutches after an automatic engine stop maydelay when engine torque is available to the vehicle's wheels, therebydelaying vehicle launch. As such, it may be desirable to provide a wayof reducing an amount of time it takes to fill transmission clutches ofa vehicle that has an engine that has been automatically stopped whilethe vehicle's transmission is engaged in park.

The inventors herein have recognized the above-mentioned issues and havedeveloped a vehicle operating method, comprising: automatically stoppingan engine via a controller without receiving specific input from adriver via a dedicated engine start/stop input; and automaticallystarting the engine via the controller in response to applying a brakepedal while the engine is automatically stopped and a transmission isengaged in park.

By automatically starting an engine of a vehicle that has beenautomatically stopped in response to applying a brake pedal while thetransmission is engaged in park, it may be possible to provide thetechnical result of reducing a delay in vehicle launch. In particular,the engine may be started before the driver shifts from park to drive sothat the engine may rotate the pump within the transmission and increasethe availability of fluid at the transmission's clutches before thetransmission is shifted into gear. Conversely, if engine starting wheredelayed until the vehicle's driver moved a shifter from park to neutral,then the buildup of transmission fluid pressure would be delayed untilshifter motion was detected. However, shifting the transmission frompark into drive requires applying a brake pedal before shifter movementis allowed so that the possibility of vehicle motion may be reduced.Starting the engine in response to the earlier application of the brakepedal allows the engine to start and the transmission fluid pump outputto increase before the shifter is moved, thereby decreasing an amount oftime between when the shifter is moved and when torque is made availableto vehicle wheels via pressurized fluid flowing from the transmissionpump to the transmission gear clutches.

The present description may provide several advantages. In particular,the approach may reduce an amount of time between when a shifter ismoved and engine torque is provided to vehicle wheels. Further, theapproach may be applied to a variety of scenarios where a vehicle'stransmission is engaged in park while the vehicle's engine isautomatically stopped. Further still, variants of the approach mayfurther improve the availability of transmission fluid to transmissionclutches after an automatic engine stop in response to road conditions.

The above advantages and other advantages, and features of the presentdescription will be readily apparent from the following DetailedDescription when taken alone or in connection with the accompanyingdrawings.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages described herein will be more fully understood by readingan example of an embodiment, referred to herein as the DetailedDescription, when taken alone or with reference to the drawings, where:

FIG. 1 is a schematic diagram of an engine;

FIG. 2 is a schematic diagram of a vehicle driveline including theengine and an automatic transmission;

FIG. 3 shows an example vehicle that includes the engine and drivelineof FIGS. 1 and 2 operating in traffic;

FIGS. 4A-4H show plots of automatic engine stopping and startingsequences; and

FIGS. 5-8 show an example method for operating a vehicle that may beautomatically stopped and started.

DETAILED DESCRIPTION

The present description is related to controlling an engine that may beautomatically stopped and started to conserve fuel. The internalcombustion engine may be configured as shown in FIG. 1. The internalcombustion engine may be included in a driveline or powertrain of avehicle as shown in FIG. 2. The engine and powertrain may be included ina vehicle as is shown in FIG. 3. The engine may be automatically stoppedand started as is shown in the sequences of FIGS. 4A-4H. The engine maybe automatically stopped and started according to the method of FIGS.5-8.

Referring to FIG. 1, internal combustion engine 10, comprising aplurality of cylinders, one cylinder of which is shown in FIG. 1, iscontrolled by electronic engine controller 12. The controller 12receives signals from the various sensors of FIG. 1 and employs thevarious actuators of FIG. 2 to adjust engine operation based on thereceived signals and instructions stored in controller memory. Forexample, controller 12 may automatically start engine 10 via activatingengine starter 96 when a human or autonomous driver applies brake pedal154.

Engine 10 is comprised of cylinder head 35 and block 33, which includecombustion chamber 30 and cylinder walls 32. Piston 36 is positionedtherein and reciprocates via a connection to crankshaft 40. Flywheel 97and ring gear 99 are coupled to crankshaft 40. Optional starter 96(e.g., low voltage (operated with less than 30 volts) electric machine)includes pinion shaft 98 and pinion gear 95. Pinion shaft 98 mayselectively advance pinion gear 95 to engage ring gear 99. Starter 96may be directly mounted to the front of the engine or the rear of theengine. In some examples, starter 96 may selectively supply torque tocrankshaft 40 via a belt or chain. In one example, starter 96 is in abase state when not engaged to the engine crankshaft.

Combustion chamber 30 is shown communicating with intake manifold 44 andexhaust manifold 48 via respective intake poppet valve 52 and exhaustpoppet valve 54. Each intake and exhaust valve may be operated by anintake camshaft 51 and an exhaust camshaft 53. The position of intakecamshaft 51 may be determined by intake camshaft sensor 55. The positionof exhaust camshaft 53 may be determined by exhaust camshaft sensor 57.Intake valves may be held open or closed over an entire engine cycle asthe engine rotates via deactivating intake valve actuator 59, which mayelectrically, hydraulically, or mechanically operate intake valves.Alternatively, intake valves may be opened and closed during a cycle ofthe engine. Exhaust valves may be held open or closed over an entireengine cycle (e.g., two engine revolutions) as the engine rotates viadeactivating exhaust valve actuator 58, which may be electrically,hydraulically, or mechanically operate exhaust valves. Alternatively,exhaust valves may be opened and closed during a cycle of the engine.

Fuel injector 66 is shown positioned to inject fuel directly intocylinder 30, which is known to those skilled in the art as directinjection. Fuel injector 66 delivers liquid fuel in proportion to thepulse width from controller 12. Fuel is delivered to fuel injector 66 bya fuel system (not shown) including a fuel tank, fuel pump, and fuelrail (not shown). In one example, a high pressure, dual stage, fuelsystem may be used to generate higher fuel pressures.

In addition, intake manifold 44 is shown communicating with turbochargercompressor 162 and engine air intake 42. In other examples, compressor162 may be a supercharger compressor. Shaft 161 mechanically couplesturbocharger turbine 164 to turbocharger compressor 162. Alternatively,compressor 162 may be electrically powered. Optional electronic throttle62 adjusts a position of throttle plate 64 to control air flow fromcompressor 162 to intake manifold 44. Pressure in boost chamber 45 maybe referred to a throttle inlet pressure since the inlet of throttle 62is within boost chamber 45. The throttle outlet is in intake manifold44. In some examples, throttle 62 and throttle plate 64 may bepositioned between intake valve 52 and intake manifold 44 such thatthrottle 62 is a port throttle. Wastegate 163 may be adjusted viacontroller 12 to allow exhaust gases to selectively bypass turbine 164to control the speed of compressor 162. Air filter 43 cleans airentering engine air intake 42. Distributorless ignition system 88provides an ignition spark to combustion chamber 30 via spark plug 92 inresponse to controller 12. Universal Exhaust Gas Oxygen (UEGO) sensor126 is shown coupled to exhaust manifold 48 upstream of catalyticconverter 70. Alternatively, a two-state exhaust gas oxygen sensor maybe substituted for UEGO sensor 126.

Converter 70 can include multiple catalyst bricks, in one example. Inanother example, multiple emission control devices, each with multiplebricks, can be used. Converter 70 can be a three-way type catalyst inone example.

A vehicle and/or engine operating mode may be selected via a humandriver via human/machine interface 8. Human/machine interface may becomprised of a switch, touch screen, or other input device.

Controller 12 is shown in FIG. 1 as a conventional microcomputerincluding: microprocessor unit 102, input/output ports 104, read-onlymemory 106 (e.g., non-transitory memory), random access memory 108(e.g., transitory memory), keep alive memory 110, and a conventionaldata bus. Controller 12 is shown receiving various signals from sensorscoupled to engine 10, in addition to those signals previously discussed,including: engine coolant temperature (ECT) from temperature sensor 112coupled to cooling sleeve 114; a position sensor 134 coupled to anaccelerator pedal 130 for sensing force applied by human driver 132; aposition sensor 154 coupled to brake pedal 150 for sensing force appliedby human driver 132, a measurement of engine manifold absolute pressure(MAP) from pressure sensor 122 coupled to intake manifold 44; an engineposition sensor from a Hall effect sensor 118 sensing crankshaft 40position; a measurement of air mass entering the engine from sensor 120;and a measurement of throttle position from sensor 68. Barometricpressure may also be sensed (sensor not shown) for processing bycontroller 12. In a preferred aspect of the present description, engineposition sensor 118 produces a predetermined number of equally spacedpulses every revolution of the crankshaft from which engine speed (RPM)can be determined.

During operation, each cylinder within engine 10 typically undergoes afour stroke cycle: the cycle includes the intake stroke, compressionstroke, expansion stroke, and exhaust stroke. During the intake stroke,generally, the exhaust valve 54 closes and intake valve 52 opens. Air isintroduced into combustion chamber 30 via intake manifold 44, and piston36 moves to the bottom of the cylinder so as to increase the volumewithin combustion chamber 30. The position at which piston 36 is nearthe bottom of the cylinder and at the end of its stroke (e.g. whencombustion chamber 30 is at its largest volume) is typically referred toby those of skill in the art as bottom dead center (BDC).

During the compression stroke, intake valve 52 and exhaust valve 54 areclosed. Piston 36 moves toward the cylinder head so as to compress theair within combustion chamber 30. The point at which piston 36 is at theend of its stroke and closest to the cylinder head (e.g. when combustionchamber 30 is at its smallest volume) is typically referred to by thoseof skill in the art as top dead center (TDC). In a process hereinafterreferred to as injection, fuel is introduced into the combustionchamber. In a process hereinafter referred to as ignition, the injectedfuel is ignited by known ignition means such as spark plug 92, resultingin combustion.

During the expansion stroke, the expanding gases push piston 36 back toBDC. Crankshaft 40 converts piston movement into a rotational torque ofthe rotary shaft. Finally, during the exhaust stroke, the exhaust valve54 opens to release the combusted air-fuel mixture to exhaust manifold48 and the piston returns to TDC. Note that the above is shown merely asan example, and that intake and exhaust valve opening and/or closingtimings may vary, such as to provide positive or negative valve overlap,late intake valve closing, or various other examples.

FIG. 2 is a block diagram of a vehicle 225 including a powertrain ordriveline 200. The powertrain of FIG. 2 includes engine 10 shown inFIG. 1. Powertrain 200 is shown including vehicle system controller 255,engine controller 12, transmission controller 254, and brake controller250. The controllers may communicate over controller area network (CAN)299. Each of the controllers may provide information to othercontrollers such as torque output limits (e.g., torque output of thedevice or component being controlled not to be exceeded), torque inputlimits (e.g., torque input of the device or component being controllednot to be exceeded), torque output of the device being controlled,sensor and actuator data, diagnostic information (e.g., informationregarding a degraded transmission, information regarding a degradedengine, information regarding degraded brakes). Further, the vehiclesystem controller 255 may provide commands to engine controller 12,transmission controller 254, and brake controller 250 to achieve driverinput requests and other requests that are based on vehicle operatingconditions.

For example, in response to a driver releasing an accelerator pedal andvehicle speed, vehicle system controller 255 may request a desired wheeltorque or a wheel power level to provide a desired rate of vehicledeceleration. The desired wheel torque may be provided by vehicle systemcontroller 255 requesting a braking torque from brake controller 250.

In other examples, the partitioning of controlling powertrain devicesmay be partitioned differently than is shown in FIG. 2. For example, asingle controller may take the place of vehicle system controller 255,engine controller 12, transmission controller 254, and brake controller250. Alternatively, the vehicle system controller 255 and the enginecontroller 12 may be a single unit while the transmission controller 254and the brake controller 250 are standalone controllers.

In this example, powertrain 200 may be powered by engine 10. Engine 10may be started with an engine starting system shown in FIG. 1. Further,torque of engine 10 may be adjusted via torque actuator 204, such as afuel injector, throttle, etc.

An engine output torque may be transmitted to torque converter 206.Torque converter 206 includes a turbine 286 to output torque to inputshaft 270. Transmission input shaft 270 mechanically couples torqueconverter 206 to automatic transmission 208. Torque converter 206 alsoincludes a torque converter bypass lock-up clutch 212 (TCC). Torque isdirectly transferred from impeller 285 to turbine 286 when TCC islocked. TCC is electrically operated by controller 254. Alternatively,TCC may be hydraulically locked. In one example, the torque convertermay be referred to as a component of the transmission.

When torque converter lock-up clutch 212 is fully disengaged, torqueconverter 206 transmits engine torque to automatic transmission 208 viafluid transfer between the torque converter turbine 286 and torqueconverter impeller 285, thereby enabling torque multiplication. Incontrast, when torque converter lock-up clutch 212 is fully engaged, theengine output torque is directly transferred via the torque converterclutch to an input shaft 270 of automatic transmission 208.Alternatively, the torque converter lock-up clutch 212 may be partiallyengaged, thereby enabling the amount of torque directly relayed to thetransmission to be adjusted. The transmission controller 254 may beconfigured to adjust the amount of torque transmitted by torqueconverter 212 by adjusting the torque converter lock-up clutch inresponse to various engine operating conditions, or based on adriver-based engine operation request. Torque converter 206 alsoincludes mechanically driven pump 283 that pressurizes fluid to operategear clutches 211. Pump 283 is driven via impeller 285, which rotates ata same speed as engine 10.

Automatic transmission 208 includes gear clutches (e.g., gears 1-10) 211and forward clutch 210. Automatic transmission 208 is a fixed step ratiotransmission. The gear clutches 211 and the forward clutch 210 may beselectively engaged to change a ratio of an actual total number of turnsof input shaft 270 to an actual total number of turns of wheels 216.Gear clutches 211 may be engaged or disengaged via adjusting fluidsupplied to the gear clutches via shift control solenoid valves 209.Torque output from the automatic transmission 208 may also be relayed towheels 216 to propel the vehicle via output shaft 260. Specifically,automatic transmission 208 may transfer an input driving torque at theinput shaft 270 responsive to a vehicle traveling condition beforetransmitting an output driving torque to the wheels 216. Transmissioncontroller 254 selectively activates or engages TCC 212, gear clutches211, and forward clutch 210. Transmission controller also selectivelydeactivates or disengages TCC 212, gear clutches 211, and forward clutch210. Transmission controller 254 removes pressurized fluid from gearclutches 211 when transmission 208 is engaged in park. Further,transmission controller 254 engages parking pawl 268 to reducetransmission shaft movement and vehicle movement when shifter 213 is ina park position. A position of shifter (e.g., Park, neutral, or drive)may be indicated via shifter position sensor 214. Parking pawl 268 mayengage output shaft 260 or a gear within transmission 208 whentransmission 208 is commanded to park. Actuator 267 may engage ordisengage parking pawl 268 via commands sent via controller 12.

Further, a frictional force may be applied to wheels 216 by engagingfriction wheel brakes 218. In one example, friction wheel brakes 218 maybe engaged in response to the driver pressing their foot on a brakepedal (not shown) and/or in response to instructions within brakecontroller 250. Further, brake controller 250 may apply brakes 218 inresponse to information and/or requests made by vehicle systemcontroller 255. In the same way, a frictional force may be reduced towheels 216 by disengaging wheel brakes 218 in response to the driverreleasing his foot from a brake pedal, brake controller instructions,and/or vehicle system controller instructions and/or information. Forexample, vehicle brakes may apply a frictional force to wheels 216 viacontroller 250 as part of an automated engine stopping procedure.

In response to a request to accelerate vehicle 225, vehicle systemcontroller may obtain a driver demand torque or power request from anaccelerator pedal or other device. Vehicle system controller 255 thencommands engine 10 in response to the driver demand torque. Vehiclesystem controller 255 requests the engine torque from engine controller12. If engine torque is less than a transmission input torque limit(e.g., a threshold value not to be exceeded), the torque is delivered totorque converter 206, which then relays at least a fraction of therequested torque to transmission input shaft 270. Transmissioncontroller 254 selectively locks torque converter clutch 212 and engagesgears via gear clutches 211 in response to shift schedules and TCClockup schedules that may be based on input shaft torque and vehiclespeed.

Accordingly, torque control of the various powertrain components may besupervised by vehicle system controller 255 with local torque controlfor the engine 10, transmission 208, and brakes 218 provided via enginecontroller 12, transmission controller 254, and brake controller 250.

As one example, an engine torque output may be controlled by adjusting acombination of spark timing, fuel pulse width, fuel pulse timing, and/orair charge, by controlling throttle opening and/or valve timing, valvelift and boost for turbo- or super-charged engines. In the case of adiesel engine, controller 12 may control the engine torque output bycontrolling a combination of fuel pulse width, fuel pulse timing, andair charge. In all cases, engine control may be performed on acylinder-by-cylinder basis to control the engine torque output.

Transmission controller 254 receives transmission input shaft positionvia position sensor 271. Transmission controller 254 may converttransmission input shaft position into input shaft speed viadifferentiating a signal from position sensor 271 or counting a numberof known angular distance pulses over a predetermined time interval.Transmission controller 254 may receive transmission output shaft torquefrom torque sensor 272. Alternatively, sensor 272 may be a positionsensor or torque and position sensors. If sensor 272 is a positionsensor, controller 254 may count shaft position pulses over apredetermined time interval to determine transmission output shaftvelocity. Transmission controller 254 may also differentiatetransmission output shaft velocity to determine transmission outputshaft acceleration. Transmission controller 254, engine controller 12,and vehicle system controller 255, may also receive additiontransmission information from sensors 277, which may include but are notlimited to pump output line pressure sensors, transmission hydraulicpressure sensors (e.g., gear clutch fluid pressure sensors), and ambienttemperature sensors.

Brake controller 250 receives wheel speed information via wheel speedsensor 223 and braking requests from vehicle system controller 255.Brake controller 250 may also receive brake pedal position informationfrom brake pedal sensor 154 shown in FIG. 1 directly or over CAN 299.Brake controller 250 may provide braking responsive to a wheel torquecommand from vehicle system controller 255. Brake controller 250 mayalso provide anti-skid and vehicle stability braking to improve vehiclebraking and stability. As such, brake controller 250 may provide a wheeltorque limit (e.g., a threshold negative wheel torque not to beexceeded) to the vehicle system controller 255.

Controller 12, or alternatively vehicle controller 255, may receive datafrom range detection and ranging system 237 (e.g., RADAR or LIDAR) todetermine a distance between vehicles. Further, controller 12 or vehiclecontroller 255 may receive data from infrastructure via radio frequencytransceiver 231. Alternatively, 231 may be comprised of a receiver andtransmitter. Controller 12 or vehicle controller 255 may also receivedata from camera 236 to determine road conditions. In some examples,controller 12 or vehicle controller 255 may receive vehicle positioninformation from global positioning system (GPS) receiver 287 todetermine the position of vehicle 225.

Referring now to FIG. 3, vehicles traveling on a road are shown. Road300 includes a first vehicle 225 including engine 10 with all thecomponents shown in FIG. 1 and a second vehicle 320 stopped (not movingon the road) in a first lane 301 of road 300. The engine of firstvehicle 225 has been automatically stopped (not rotating). Vehicle rangesensors 337 (e.g. RADAR or LIDAR) onboard vehicle 225 may report adistance D1 between first vehicle 250 and second vehicle 320 when secondvehicle 320 is traveling in the path (e.g., same lane) of first vehicle225 and when there are no intermediate vehicles between first vehicle225 and second vehicle 320. The distance D1 may be updated at apredetermined rate (e.g., every 100 milliseconds) and supplied tocontroller 12 shown in FIG. 1. If the distance D1 increases after firstvehicle 225 is stopped, controller 12 may determine that second vehicle320 is moving while the engine 10 of first vehicle 225 is automaticallystopped with the transmission in park so that engine 10 may beautomatically started before the vehicle's driver shifts from park todrive. By starting the engine earlier than the driver shifts thetransmission, it may be possible for the transmissions pump topressurize fluid in the transmission so that gears of the transmissionmay be shifted without hesitation when commanded by the driver. Theability to shift into gear on command without having for thetransmission pump to build pressure may reduce vehicle launch time afterthe engine has been automatically stopped and the transmission isengaged in park.

Camera 336 may also detect road conditions such as objects in the pathof vehicle 225, traffic signs that are being approached by vehicle 225,operating states of traffic lights 356, highway on ramps, etc. Camera336 may supply such information in the form of data to controller 12 orvehicle controller 255 that is in communication with controller 12. Ifcamera 336 detects second vehicle 320 moving in front of first vehicle225 while first vehicle 225 is stopped, controller 12 may determine thatsecond vehicle 320 is moving. Similarly, if camera 336 detects thattraffic light controller 355 has just changed traffic light 356 from redto green while first vehicle 225 is stopped and while engine 10 isautomatically stopped with the transmission in park in front of trafficlight 356, then controller 12 may determine that acceleration of firstvehicle is expected from data provided by the camera so that the engine10 may be automatically started sooner. Starting the automaticallystopped engine sooner may prevent vehicle launch delays.

Receiver 231 may receive traffic data from traffic signal controller 355that indicates traffic light phase and timing. Receiver 231 maycommunicate the same information to controller 12 of FIG. 1 andcontroller 12 may determine that vehicle acceleration or an increase ofdriver demand torque is anticipated or expected from the data. Forexample, if controller 12 determines that traffic light 356 is about tochange from red to green while first vehicle 225 is stopped and whileengine 10 is automatically stopped with the transmission in park infront of traffic signal 356, controller 12 may determine that firstvehicle 225 is expected to accelerate shortly thereafter. Engine 10 maythen be automatically started in response to the indication of expectedor anticipated acceleration of first vehicle 225. By starting the engine10 earlier than the driver shifts the transmission, it may be possiblefor the transmissions pump to pressurize fluid in the transmission sothat gears of the transmission may be shifted without hesitation whencommanded by the driver.

Thus, the various sensors shown in FIG. 3 may provide data that allowscontroller 12 or vehicle controller 255 to anticipate vehicle movementof vehicle 225 while vehicle 225 is stopped and its engine isautomatically stopped. The data may be processed while at a rate thatexceeds a human's response time so that engine 10 may be started inanticipation of the driver shifting from park to a gear so that pressuremay be made available to shift transmission gears.

Thus, the system of FIGS. 1-3 provide for a system, comprising: avehicle including an engine; a transmission coupled to the enginevehicle sensors configured to sense motion of vehicles in the path ofthe vehicle; and a controller including executable instructions storedin non-transitory memory to automatically stop the engine, andinstructions to automatically start the engine after the engine is mostrecently automatically stopped, the engine automatically started whilethe transmission is engaged in park in response to the vehicle sensorsdetecting motion of vehicles in the path of the vehicle. The systemfurther comprises additional instructions to automatically start theengine after the engine is most recently automatically stopped, theengine automatically started while the transmission is engaged in parkin response to output of an infrastructure device that broadcasts roadconditions. The system further comprises additional instructions toautomatically start the engine after the engine is most recentlyautomatically stopped, the engine automatically started while thetransmission is engaged in park in response to a human driver applying abrake pedal while the engine is automatically stopped and a transmissionis engaged in park. The system includes where the engine isautomatically stopped while the transmission is in park. The systemincludes where the engine is automatically stopped while thetransmission is in drive. The system includes where the engine isautomatically stopped while the transmission is in neutral. The systemincludes where the vehicle sensors configured to sense motion ofvehicles include light detection and ranging (LIDAR) systems. The systemincludes where the vehicle sensors configured to sense motion ofvehicles include radio detection and ranging (RADAR) systems.

Referring now to FIG. 4A, an example vehicle operating sequence isshown. The sequence of FIG. 4A may be provided according to the methodof FIGS. 5-8 in conjunction with the system of FIGS. 1-3. The plotsshown in FIG. 4A occur at the same time and are aligned in time. Thevertical lines at times t0-t3 represent times of interest in thesequence.

The sequences of FIGS. 4B-4F include similar plots that show the samevariables being plotted against time. Therefore, for the sake ofbrevity, the description of each plot is not repeated. Note that thetraces for each plot have different identification numbers even thoughthey represent the same variables. For example, trace 402 in FIG. 4Arepresents transmission gear and trace 410 in FIG. 4B also representstransmission gear. A human driver or autonomous driver may apply andrelease the brake pedal as is shown in the sequences. The human drivermay also shift the transmission as is shown in the sequences.

The first plot from the top of FIG. 4A is a plot of engaged transmissionstate versus time. The vertical axis represents engaged transmissionstate and the transmission states are listed along the vertical axis.The letter “D” indicates drive where the transmission may be engaged(e.g., gear clutches transfer torque) in a forward gear (e.g., 1-10) andpressurized fluid is supplied to one or more gear clutches, the letter“N” indicates neutral and pressurized fluid is supplied to one or moregear clutches, the letter “P” indicates park and fluid pressure isrelieved from all gear clutches to disengage the gear clutches (e.g.,the gear clutches do not transfer torque) while a parking pawl isengaged to limit motion of the wheels and driveline. The horizontal axisrepresents time and time increases from the left side of the figure tothe right side of the figure. Trace 402 represents transmissionengagement state.

The second plot from the top of FIG. 4A is a plot of brake pedal stateversus time. The vertical axis represents brake pedal state. The brakepedal is applied or on when trace 404 is near the arrow of the verticalaxis. The brake pedal is not applied or off when trace 404 is near thehorizontal axis. The horizontal axis represents time and time increasesfrom the left side of the figure to the right side of the figure.

The third plot from the top of FIG. 4A is a plot of engine operatingstate versus time. The vertical axis represents engine operating state.The engine is on (e.g., combusting air and fuel) when trace 406 is at ahigher level near the vertical axis arrow. The engine is off (e.g., notcombusting air and fuel) when trace 406 is at a lower level near thehorizontal axis. The horizontal axis represents time and time increasesfrom the left side of the figure to the right side of the figure.

The fourth plot from the top of FIG. 4A is a plot an automatic enginestop request state versus time. The vertical axis represents automaticengine stop request state. An automatic engine stop request is presentwhen trace 408 is at a higher level near the vertical axis arrow. Anautomatic engine stop request is not present when trace 408 is at alower level near the horizontal axis. The engine is automaticallystopped when the automatic engine stop request state is at the higherlevel. The engine is automatically started when the automatic enginestop request trace 408 transitions from the higher level to the lowerlevel. The engine remains on when the automatic engine stop requesttrace is at the lower level. The horizontal axis represents time andtime increases from the left side of the figure to the right side of thefigure.

At time t0, the engine is on and the transmission is engaged in drive.The brake pedal is not applied and the automatic engine stop request isnot asserted. Such conditions may be present while a vehicle istraveling on a road. At time t1, the driver (human or autonomous)applies the brake pedal causing vehicle speed to be reduced (not shown).As time increases, the engine is automatically stopped at time t2 asindicated by the automatic stop request being asserted and the enginestate transitioning to “off.” The engine may be automatically stopped inresponse to various vehicle operating conditions including driver demandtorque being less than a threshold torque and battery state of charge(SOC) being greater than a threshold SOC.

Between time t2 and time t3, the driver shifts the transmission fromdrive to park and fully releases the brake pedal. The transmission gearclutches are released (e.g., fluid pressure applied to the gear clutchesis reduced until the gear clutch's capacity to transfer torque is zero)and a parking pawl of the transmission is engaged to limit vehiclemovement when the transmission is engaged in park. By reducing pressurein the gear clutches the engine is decoupled from the vehicle's rearwheels, but fluid pressure supplied to the clutches has to be increasedbefore engine torque may be transmitted to the vehicle's wheels.

At time t3, the driver applies the brake pedal to begin the process ofshifting from park into drive. The engine is automatically started eventhough the driver does not shift from park to drive. The engine isstarted so that pressure output from the transmission pump may beincreased before the transmission is shifted into drive. The higheroutlet pressure of the transmission pump may allow the transmission toshift to drive (e.g., first gear) in a shorter amount of time ascompared to if the engine were restarted when the transmission wasshifted from park to drive. Thus, the controller automatically restartsthe engine in response to the brake pedal being applied after the brakepedal was fully released.

In this way, the engine may be started early while the transmission isin park to increase output of the transmission pump before the drivermoves the vehicle's shifter into drive. The brake pedal being appliedbefore the transmission is shifted provides lead time to start theengine and increase transmission pump output so that the gears mayengage quickly when the gear shifter enters the drive position.

Referring now to FIG. 4B, a second engine automatic stopping andstarting sequence is shown. At time t5, the transmission is in drive asis indicated by trace 410 and the engine is on as is indicated by trace414. The driver is applying the brake pedal and the automatic enginestop request is not asserted. The vehicle may be stopped or deceleratingduring such conditions.

At time t6, the driver shifts the transmission into neutral whileapplying the brake pedal. The engine remains on and the automatic enginestop request is not asserted. Such conditions may be present when thevehicle is stopped in a traffic jam. The driver fully releases the brakepedal after the transmission is shifted into park. The vehicle does notmove when the brake pedal is released since the transmission is engagedin park.

At time t7, the engine is automatically stopped as indicated by enginestate trace 414 in response to the automatic engine stop requestindicated by trace 416. The engine is automatically stopped in responseto vehicle conditions, such as driver demand torque being less than athreshold torque and battery SOC being greater than a threshold SOC. Theengine stop is indicated by trace 414 transitioning to a lower level andtrace 416 transitioning to a higher level. The driver shifts thetransmission into park while the brake pedal is fully released betweentime t7 and time t8.

At time t8, the driver applies the brake pedal and the automaticallystopped engine is restarted in response to the brake pedal being appliedas is indicated by engine state trace 414 transitioning to a higherlevel and the automatic engine stop request state transitioning to alower level. The transmission is engaged in park, which indicates thatthe driver has to first apply the brake pedal before shifting from parkto neutral or drive. Therefore, applying the brake pedal when thetransmission is engaged in park may be interpreted as a leadingindicator that the driver will shortly be requesting to accelerate thevehicle. As such, the engine may be started earlier when the brake pedalis applied, instead of later when the gear shifter is moved from park todrive. Consequently, fluid pressure to shift the gear clutches may beincrease earlier so that the transmission may be timely shifted frompark to drive.

Referring now to FIG. 4C, a third engine automatic stopping and startingsequence is shown. At time t10, the transmission is in drive as isindicated by trace 420 and the engine is on as is indicated by trace424. The driver is applying the brake pedal and the automatic enginestop request is not asserted. The vehicle may be stopped or deceleratingduring such conditions.

At time t11, the driver shifts the transmission into neutral whileapplying the brake pedal. The engine remains on and the automatic enginestop request is not asserted. Such conditions may be present when thevehicle is stopped in a traffic jam. The driver continues to apply thebrake pedal after the transmission is shifted into neutral.

At time t12, the engine is automatically stopped as indicated by enginestate trace 424 in response to the automatic engine stop requestindicated by trace 426. The engine is automatically stopped in responseto vehicle conditions, such as driver demand torque being less than athreshold torque and battery SOC being greater than a threshold SOC. Theengine stop is indicated by trace 424 transitioning to a lower level andtrace 426 transitioning to a higher level.

Between time t12 and time t13, the driver first shifts the transmissioninto park while the brake pedal is applied, then the driver releases thebrake pedal. The engine remains off and the automatic engine stoprequest remains on or asserted.

At time t13, the driver applies the brake pedal and the automaticallystopped engine is restarted in response to the brake pedal being appliedas is indicated by engine state trace 424 transitioning to a higherlevel and the automatic engine stop request state 426 transitioning to alower level. The transmission is engaged in park, which allowsapplication of the brake pedal to be interpreted as an early indicationof a driver requesting vehicle acceleration. Therefore, the engine maybe started earlier when the brake pedal is applied, instead of laterwhen the gear shifter is moved from park to drive.

Referring now to FIG. 4D, a fourth engine automatic stopping andstarting sequence is shown. At time t15, the transmission is in drive asis indicated by trace 430 and the engine is on as is indicated by trace434. The driver is applying the brake pedal and the automatic enginestop request is not asserted. The vehicle may be stopped or deceleratingduring such conditions.

At time t16, the driver shifts the transmission into park while applyingthe brake pedal. The engine remains on and the automatic engine stoprequest is not asserted. Such conditions may be present when the vehicleis fully stopped in a parking lot or a traffic jam. At time t17, theengine is automatically stopped as indicated by engine state trace 434in response to the automatic engine stop request indicated by trace 436.The engine is automatically stopped in response to vehicle conditions,such as driver demand torque being less than a threshold torque andbattery SOC being greater than a threshold SOC. The engine stop isindicated by trace 434 transitioning to a lower level and trace 436transitioning to a higher level. The transmission remains in park andthe brake pedal remains in an applied state as indicated by trace 432being at a higher level.

Between time t17 and time t18, the driver fully releases the brake pedalas indicated by trace 432 transitioning to a lower level. Thetransmission remains in park and the engine remains stopped.

At time t18, the driver applies the brake pedal and the automaticallystopped engine is restarted in response to the brake pedal being appliedas is indicated by engine state trace 434 transitioning to a higherlevel and the automatic engine stop request state 436 transitioning to alower level. The transmission is engaged in park, which indicates thatthe brake pedal may be used as an early indication of a driver's requestto accelerate the vehicle. Thus, even if the transmission was engaged inpark before the engine was automatically stopped, application of thebrake pedal may be used as an indication to restart the engine so thatfluid supplied to transmission gear clutches is at a sufficient pressureto enable gear shifting and torque delivery from the engine to vehiclewheels.

Referring now to FIG. 4E, a fifth engine automatic stopping and startingsequence is shown. At time t20, the transmission is in drive as isindicated by trace 440 and the engine is on as is indicated by trace444. The driver is applying the brake pedal and the automatic enginestop request is not asserted. The vehicle may be stopped or deceleratingduring such conditions.

At time t21, the driver shifts the transmission into park while applyingthe brake pedal.

The engine remains on and the automatic engine stop request is notasserted. Such conditions may be present when the vehicle is stopped ina traffic jam. The driver fully releases the brake pedal after thetransmission is shifted into park and the vehicle does not move when thebrake pedal is released since the transmission is engaged in park.

At time t22, the engine is automatically stopped as indicated by enginestate trace 444 in response to the automatic engine stop requestindicated by trace 446. The engine is automatically stopped in responseto vehicle conditions, such as driver demand torque being less than athreshold torque and battery SOC being greater than a threshold SOC. Theengine stop is indicated by trace 444 transitioning to a lower level andtrace 446 transitioning to a higher level. At time t23, the driverapplies the brake pedal and the automatically stopped engine isrestarted in response to the brake pedal being applied as is indicatedby engine state trace 444 transitioning to a higher level and theautomatic engine stop request state 446 transitioning to a lower level.The transmission is engaged in park, which indicates that the brakepedal being applied may be used as an early indication that the driverwill soon be demanding torque to accelerate the vehicle. Thus, theengine may be automatically restarted in response to applying a brakepedal even if the brake pedal was released before the engine wasautomatically stopped.

Referring now to FIG. 4F, a sixth engine automatic stopping and startingsequence is shown. At time t25, the transmission is in drive as isindicated by trace 450 and the engine is on as is indicated by trace454. The driver is applying the brake pedal and the automatic enginestop request is not asserted. The vehicle may be stopped or deceleratingduring such conditions.

At time t26, the driver shifts the transmission into park while applyingthe brake pedal. The engine remains on and the automatic engine stoprequest is not asserted. Such conditions may be present when the vehicleis stopped in a parking lot or a traffic jam. The driver does not fullyrelease the brake pedal after the transmission is shifted into park.

At time t27, the engine is automatically stopped as indicated by enginestate trace 454 in response to the automatic engine stop requestindicated by trace 456. The engine is automatically stopped in responseto vehicle conditions, such as driver demand torque being less than athreshold torque and battery SOC being greater than a threshold SOC. Theengine stop is indicated by trace 454 transitioning to a lower level andautomatic engine stop request trace 456 transitioning to a higher level.The driver continues to apply the brake pedal as indicated by trace 452remaining at a higher level.

At time t28, a threshold amount of time has elapsed since the engine wasautomatically stopped at time t27. Further, the brake pedal has not beenrelease since the engine was automatically stopped at time t27.Therefore, the engine is automatically restarted without the driverhaving released the brake pedal after the engine was automaticallystopped. The engine is restarted because there is no indication that thedriver intends to release the brake pedal and because restarting theengine allows pressure of transmission fluid to increase before thedriver may shift from park to drive. As such, the engine may be startedbefore the transmission is shifted into drive even if the driverprovides no indication of a vehicle launch before shifting thetransmission. Further, in some examples, if the engine has been stoppedfor only a short amount of time and the driver does not release thebrake pedal after the engine is automatically stopped while thetransmission is in park, the engine may be restarted in response to thedriver shifting out of park. Consequently, the engine may be started andtransmission fluid pressure may be increased before the transmission isengaged into drive. Thus, the engine may be restarted even if the driverfails to release the brake before the transmission shifter moves to thedrive position.

Referring now to FIG. 4G, it includes plots of the same variables asFIGS. 4A-4F. For the sake of brevity, the description of transmissiongear, brake pedal state, engine state, and engine automatic stop requestwill not be repeated, but these variables in FIG. 4G are the same asthey are described in FIG. 4A. FIG. 4G includes also includes a plot ofvehicle motion detected state. The vertical axis represents vehiclemotion detected state. The vehicle motion detected state is a variablethat indicates whether or not motion of a vehicle in the path of thepresent vehicle is detected via sensors onboard the present vehicle.Motion of a vehicle in the path of the present vehicle described hereinis detected when trace 468 is at a high level near the vertical axisarrow. Motion of a vehicle in the path of the present vehicle describedherein is not detected when trace 468 is at a lower level near thehorizontal axis. Motion of the vehicle may be detected via RADAR, LIDAR,camera, or other known device. The horizontal axis represents time andtime increases from the left side of the plot to the right side of theplot.

At time t30, the transmission is in drive as is indicated by trace 460and the engine is on as is indicated by trace 464. The driver isapplying the brake pedal and the automatic engine stop request is notasserted. The vehicle may be stopped or decelerating during suchconditions.

At time t31, the engine is automatically stopped as indicated by enginestate trace 464 in response to the automatic engine stop requestindicated by trace 466. The engine is automatically stopped in responseto vehicle conditions, such as driver demand torque being less than athreshold torque and battery SOC being greater than a threshold SOC. Theengine stop is indicated by trace 464 transitioning to a lower level andautomatic engine stop request trace 466 transitioning to a higher level.The driver continues to apply the brake pedal as indicated by trace 462remaining at a higher level. The driver leaves the transmission engagedin drive.

At time t32, the driver shifts the transmission into park while applyingthe brake pedal. The driver then releases the brake pedal a short timelater. The engine remains off and the automatic engine stop requestremains asserted. The engine remains automatically stopped between timet32 and time t33.

At time t33, the vehicle motion detected state changes to a high levelto indicate that a vehicle in the path of the present vehicle isbeginning to move. The vehicle may begin to move in response to othertraffic in a traffic jam beginning to move (not shown). The automaticengine stop request is withdrawn in response to the vehicle motiondetected state being asserted. The engine is started in response to theautomatic engine stop request being withdrawn. The driver applies thebrake pedal shortly after time t33 and then the driver shifts thetransmission into drive. Thus, the engine is started before the drivershifts the transmission into drive so that there is sufficient pressureavailable to close the transmission gear clutches.

Thus, vehicle motion detecting sensors may provide even more time torestart an engine before a driver requests engine torque to be deliveredto the vehicle's wheels. The additional time may allow the engine toincrease transmission pump output pressure so that transmission gearsmay be shifted as is desired. Further, the additional time may allow theengine's torque capacity to be increased so that the driveline hascapacity to meet driver demand torque.

Referring now to FIG. 4H, it includes plots of the same variables asFIGS. 4A-4F. For the sake of brevity, the description of transmissiongear, brake pedal state, engine state, and engine automatic stop requestwill not be repeated, but these variables in FIG. 4H are the same asthey are described in FIG. 4A. FIG. 4H includes also includes a plot ofvehicle motion notification state. The vertical axis represents vehiclemotion notification state. The vehicle motion notification stateindicates if infrastructure (e.g., traffic controllers, bridgecontrollers, rail road crossing controllers, etc.) or other vehicles areproviding data that indicates that the vehicle described herein may soonhave clearance to proceed in its present direction. For example, thedata may be an indication from infrastructure that a rail road crossingis about to open to allow traffic to proceed. In another example, theindication may be from a second vehicle in the path of the vehicledescribed herein that the second vehicle is moving, thereby providingclearance to the vehicle described herein to move. The vehicle motionnotification state is asserted when trace 478 is at a high level nearthe vertical axis arrow, which indicates that the vehicle describedherein may soon have clearance to proceed on its journey. The vehiclemotion notification is not asserted when trace 478 is at a lower levelnear the horizontal axis. The horizontal axis represents time and timeincreases from the left side of the plot to the right side of the plot.

At time t35, the transmission is in drive as is indicated by trace 470and the engine is on as is indicated by trace 474. The driver isapplying the brake pedal and the automatic engine stop request is notasserted. The vehicle may be stopped or decelerating during suchconditions.

At time t36, the engine is automatically stopped as indicated by enginestate trace 474 in response to the automatic engine stop requestindicated by trace 476. The engine is automatically stopped in responseto vehicle conditions, such as driver demand torque being less than athreshold torque and battery SOC being greater than a threshold SOC. Theengine stop is indicated by trace 474 transitioning to a lower level andautomatic engine stop request trace 476 transitioning to a higher level.The driver continues to apply the brake pedal as indicated by trace 472remaining at a higher level. The driver leaves the transmission engagedin drive.

At time t37, the driver shifts the transmission into park while applyingthe brake pedal. The driver then releases the brake pedal a short timelater. The engine remains off and the automatic engine stop requestremains asserted. The engine remains automatically stopped between timet36 and time t37.

At time t38, the vehicle motion notification state changes to a highlevel to indicate that the vehicle described herein may soon be allowedto move. The vehicle described herein may be allowed to move in responseto a traffic signal changing, a railroad gate opening, or anotherindication from infrastructure or other vehicles. The automatic enginestop request is withdrawn in response to the vehicle motion notificationstate being asserted. The engine is started in response to the automaticengine stop request being withdrawn. The driver applies the brake pedalshortly after time t38 and then the driver shifts the transmission intodrive. Thus, the engine is started before the driver shifts thetransmission into drive so that there is sufficient pressure availableto close the transmission gear clutches.

Thus, infrastructure and other vehicles may provide even more time torestart an engine before a driver requests engine torque to be deliveredto the vehicle's wheels. The additional time may allow the engine toincrease transmission pump output pressure so that transmission gearsmay be shifted as is desired. Further, the additional time may allow theengine's torque capacity to be increased so that the driveline hascapacity to meet driver demand torque.

Referring now to FIGS. 5-8, a method for operating a vehicle is shown.At least portions of method 500 may be implemented as executablecontroller instructions stored in non-transitory memory. Additionally,portions of method 500 may be actions taken in the physical world totransform an operating state of an actuator or device. The method ofFIGS. 5-8 may be incorporated into the system of FIGS. 1-3 as executableinstructions stored in non-transitory memory.

At 502, method 500 operates an engine according to driver demand torqueand engine speed. The driver demand torque may be input via thevehicle's accelerator pedal and accelerator pedal position may beconverted into a driver demand torque. The engine air amount, sparktiming, and fuel amount may then be determined via maps and/or functionsthat reference the tables or functions via engine speed and driverdemand torques. Values in the tables may be empirically determined viaoperating the engine on a dynamometer and adjusting engine operationresponsive to the driver demand torque and engine speed. Method 500proceeds to 504.

At 504, method 500 judges if the vehicle is stopped in traffic and thevehicle includes sensors for determining the motion of vehicles intraffic (e.g., motion of a vehicle in front of the vehicle describedherein). In one example, method 500 may judge if the vehicle includessensors to determine traffic motion based on values of variables storedin controller memory. For example, if the vehicle described hereinincludes a camera a first variable stored in memory may have a value ofone. However, if the vehicle described herein does not include a camera,the value of the variable may be zero. Method 500 also judges if thepresent vehicle is stopped in traffic. In one example, method 500 mayjudge that the vehicle is stopped in traffic if a global positioningsystem indicates that the vehicle described herein is traveling on aroad and stopped. If method 500 judges that vehicle is stopped intraffic and the vehicle includes sensors for determining the motion ofvehicles in traffic, then the answer is yes and method 500 proceeds to530 of FIG. 7. Otherwise, the answer is no and method 500 proceeds to506.

At 506, method 500 judges if the vehicle is stopped in traffic and ifthe vehicle is in communication with other vehicles and/orinfrastructure (e.g., electronic traffic controllers, bridge trafficcontrollers, traffic signals, etc.). In one example, method 500 mayjudge if the vehicle includes sensors to communicate with other vehiclesand/or infrastructure based on values of variables stored in controllermemory. For example, if the vehicle described herein includes atransceiver or receiver for communicating with other vehicles and/orinfrastructure then a first variable stored in memory may have a valueof one. However, if the vehicle described herein does not include areceiver for communicating with other vehicles and/or infrastructure,then the value of the variable may be zero. Method 500 also judges ifthe present vehicle is stopped in traffic. In one example, method 500may judge that the vehicle is stopped in traffic if a global positioningsystem indicates that the vehicle described herein is traveling on aroad and stopped. If method 500 judges that vehicle is stopped intraffic and the vehicle includes sensors for communicating with othervehicles and/or infrastructure, then the answer is yes and method 500proceeds to 560 of FIG. 8. Otherwise, the answer is no and method 500proceeds to 508 of FIG. 6.

At 508, method 500 judges if conditions are present to automaticallystop the vehicle's engine (e.g., stop the engine via the controllerresponding to inputs other than a user or driver input that has aspecific dedicated function of requesting engine stop or start). In oneexample, method 500 may automatically stop the engine when driver demandtorque is less than a threshold torque and when engine speed is lessthan a threshold speed. Further, method 500 may require that otherconditions be present to request automatic engine stopping. For example,method 500 may require that battery state of charge (SOC) is greaterthan a threshold SOC to permit automatic engine stopping. If method 500judges that conditions are present for automatic engine stopping, theanswer is yes and method 500 proceeds to 510. Otherwise, the answer isno and method 500 proceeds to exit.

At 510, method 500 judges if the vehicle's transmission is commanded topark. In one example, method 500 may determine that the vehicle'stransmission is commanded to park in response to a position of ashifter. The position of the shifter may be determined via a sensor. Ifmethod 500 judges that the transmission is commanded park (e.g., theshifter's position indicates park), the answer is yes and method 500proceeds to 512. Otherwise, the answer is no and method 500 proceeds to520.

At 512, method 500 engages the parking pawl and restricts movement ofthe vehicle's wheels. In addition, pressure of fluid supplied totransmission gear clutches is reduced such that the transmission gearclutches transfer zero torque. Thus, the transmission gear clutches areopened. Method 500 proceeds to 514 after engaging the parking pawl andreducing pressure of fluid supplied to transmission gear clutches.

At 514, method 500 automatically stops the engine. The engine may bestopped via ceasing to supply fuel and spark to the engine. Rotation ofthe engine stops when fuel and spark are not supplied to the engine.Method 500 proceeds to 516.

At 516, method 500 judges if the vehicle's brake pedal has been applied(e.g., fully or partially) without being release for longer than athreshold amount of time since the engine was most recentlyautomatically stopped. In one example, a counter may be activated whenthe engine is automatically stopped at 514 and the timer may beincremented as long as the driver applies the brake pedal. If method 500judges that the brake pedal has been applied for longer than a thresholdamount of time without being released since the engine was most recentlyautomatically stopped, then the answer is yes and method 500 proceeds to517. Otherwise, the answer is no and method 500 proceeds to 518.

At 517, method 500 automatically starts the engine via engaging astarter, rotating the engine, and supplying spark and fuel to theengine. The engine is automatically started without the driver applyingan input that has a dedicated sole function of starting and stopping theengine (e.g., an ignition switch or pushbutton). Method 500 proceeds toexit after automatically starting the engine.

At 518, method 500 judges if the vehicle's brake pedal has been appliedafter the brake pedal was fully released while the engine wasautomatically stopped. If method 500 judges that the brake pedal hasbeen applied after the brake pedal was fully released while the enginewas automatically stopped, then the answer is yes and method 500proceeds to 517. Otherwise, the answer is no and method 500 returns to510.

At 520, method 500 automatically stops the engine. The engine may bestopped via ceasing to supply fuel and spark to the engine. Rotation ofthe engine stops when fuel and spark are not supplied to the engine.Method 500 proceeds to 522.

At 522, method 500 judges if the brake pedal has been fully released orif battery SOC is less than a threshold SOC. Method 500 may judge thatthe brake pedal has been fully released based on a position of a brakepedal sensor. For example, if output of the brake pedal sensor is lessthan a threshold voltage, then method 500 may determine that the brakepedal is fully released. Method 500 may judge that battery SOC is lessthan a threshold SOC based on battery voltage. If method 500 judges thatthe brake pedal has been fully released or if the battery SOC is lessthan the threshold SOC, the answer is yes and method 500 proceeds to524. Otherwise, the answer is no and method 500 returns to 510.

At 524, method 500 automatically starts the engine via engaging astarter, rotating the engine, and supplying spark and fuel to theengine. The engine is automatically started without the driver applyingan input that has a dedicated sole function of starting and stopping theengine (e.g., an ignition switch or pushbutton). Method 500 proceeds toexit after automatically starting the engine.

At 530, method 500 judges if conditions are present to automaticallystop the vehicle's engine (e.g., stop the engine via the controllerresponding to inputs other than a user or driver input that has aspecific dedicated function of requesting engine stop or start). Ifmethod 500 judges that conditions are present for automatic enginestopping, the answer is yes and method 500 proceeds to 532. Otherwise,the answer is no and method 500 proceeds to exit.

At 532, method 500 judges if the vehicle's transmission is commanded topark. In one example, method 500 may determine that the vehicle'stransmission is commanded to park in response to a position of ashifter. The position of the shifter may be determined via a sensor. Ifmethod 500 judges that the transmission is commanded park (e.g., theshifter's position indicates park), the answer is yes and method 500proceeds to 534. Otherwise, the answer is no and method 500 proceeds to550.

At 534, method 500 engages the parking pawl and restricts movement ofthe vehicle's wheels. In addition, pressure of fluid supplied totransmission gear clutches is reduced such that the transmission gearclutches transfer zero torque. Thus, the transmission gear clutches areopened. Method 500 proceeds to 536 after engaging the parking pawl andreducing pressure of fluid supplied to transmission gear clutches.

At 536, method 500 automatically stops the engine. The engine may bestopped via ceasing to supply fuel and spark to the engine. Rotation ofthe engine stops when fuel and spark are not supplied to the engine.Method 500 proceeds to 538.

At 538, method 500 judges if motion of a vehicle in the path of thepresent vehicle (e.g., the vehicle described herein) is detected. Motionof the vehicle in the present vehicle's path of travel may be detectedvia RADAR, LIDAR, a camera, or other known device or system. If method500 judges that the vehicle in the path of the present vehicle ismoving, the answer is yes and method 500 proceeds to 540. Otherwise, theanswer is no and method 500 returns to 532.

At 540, method 500 automatically starts the engine via engaging astarter, rotating the engine, and supplying spark and fuel to theengine. The engine is automatically started without the driver applyingan input that has a dedicated sole function of starting and stopping theengine (e.g., an ignition switch or pushbutton). Method 500 proceeds toexit after automatically starting the engine. By automatically startingthe engine in response to an indication that a vehicle in the travelpath of the present vehicle is moving, it may be possible to start theengine and increase transmission fluid pump output so that transmissiongears may be timely engaged when the driver shifts to drive.

At 550, method 500 automatically stops the engine. The engine may bestopped via ceasing to supply fuel and spark to the engine. Rotation ofthe engine stops when fuel and spark are not supplied to the engine.Method 500 proceeds to 552.

At 552, method 500 judges if the brake pedal has been fully released orif battery SOC is less than a threshold SOC. Method 500 may judge thatthe brake pedal has been fully released based on a position of a brakepedal sensor. For example, if output of the brake pedal sensor is lessthan a threshold voltage, then method 500 may determine that the brakepedal is fully released. Method 500 may judge that battery SOC is lessthan a threshold SOC based on battery voltage. If method 500 judges thatthe brake pedal has been fully released or if the battery SOC is lessthan the threshold SOC, the answer is yes and method 500 proceeds to554. Otherwise, the answer is no and method 500 returns to 532.

At 554, method 500 automatically starts the engine via engaging astarter, rotating the engine, and supplying spark and fuel to theengine. The engine is automatically started without the driver applyingan input that has a dedicated sole function of starting and stopping theengine (e.g., an ignition switch or pushbutton). Method 500 proceeds toexit after automatically starting the engine.

At 560, method 500 judges if conditions are present to automaticallystop the vehicle's engine (e.g., stop the engine via the controllerresponding to inputs other than a user or driver input that has aspecific dedicated function of requesting engine stop or start). Ifmethod 500 judges that conditions are present for automatic enginestopping, the answer is yes and method 500 proceeds to 562. Otherwise,the answer is no and method 500 proceeds to exit.

At 562, method 500 judges if the vehicle's transmission is commanded topark. In one example, method 500 may determine that the vehicle'stransmission is commanded to park in response to a position of ashifter. The position of the shifter may be determined via a sensor. Ifmethod 500 judges that the transmission is commanded park (e.g., theshifter's position indicates park), the answer is yes and method 500proceeds to 564. Otherwise, the answer is no and method 500 proceeds to580.

At 564, method 500 engages the parking pawl and restricts movement ofthe vehicle's wheels. In addition, pressure of fluid supplied totransmission gear clutches is reduced such that the transmission gearclutches transfer zero torque. Thus, the transmission gear clutches areopened. Method 500 proceeds to 566 after engaging the parking pawl andreducing pressure of fluid supplied to transmission gear clutches.

At 566, method 500 automatically stops the engine. The engine may bestopped via ceasing to supply fuel and spark to the engine. Rotation ofthe engine stops when fuel and spark are not supplied to the engine.Method 500 proceeds to 568.

At 568, method 500 judges if the present vehicle is receiving data thatindicates that the present vehicle's travel path is clearing or is aboutto clear. An indication of the present vehicle's travel path clearingmay be provided via vehicle to vehicle communication, communication withinfrastructure such as an electronic traffic controller or rail roadcrossing controller, or other traffic control device. If method 500judges that the present vehicle is receiving data that indicates thatthe present vehicle's travel path is clearing or is about to clear, theanswer is yes and method 500 proceeds to 570. Otherwise, the answer isno and method 500 returns to 562.

At 570, method 500 automatically starts the engine via engaging astarter, rotating the engine, and supplying spark and fuel to theengine. The engine is automatically started without the driver applyingan input that has a dedicated sole function of starting and stopping theengine (e.g., an ignition switch or pushbutton). Method 500 proceeds toexit after automatically starting the engine. By automatically startingthe engine in response to data from other vehicles or infrastructure, itmay be possible to start the engine and increase transmission fluid pumpoutput so that transmission gears may be timely engaged when the drivershifts to drive.

At 580, method 500 automatically stops the engine. The engine may bestopped via ceasing to supply fuel and spark to the engine. Rotation ofthe engine stops when fuel and spark are not supplied to the engine.Method 500 proceeds to 582.

At 582, method 500 judges if the brake pedal has been fully released orif battery SOC is less than a threshold SOC. Method 500 may judge thatthe brake pedal has been fully released based on a position of a brakepedal sensor. For example, if output of the brake pedal sensor is lessthan a threshold voltage, then method 500 may determine that the brakepedal is fully released. Method 500 may judge that battery SOC is lessthan a threshold SOC based on battery voltage. If method 500 judges thatthe brake pedal has been fully released or if the battery SOC is lessthan the threshold SOC, the answer is yes and method 500 proceeds to584. Otherwise, the answer is no and method 500 returns to 562.

At 584, method 500 automatically starts the engine via engaging astarter, rotating the engine, and supplying spark and fuel to theengine. The engine is automatically started without the driver applyingan input that has a dedicated sole function of starting and stopping theengine (e.g., an ignition switch or pushbutton). Method 500 proceeds toexit after automatically starting the engine.

In these ways, it may be possible to start an engine early before adriver (e.g., human or autonomous) of a vehicle commands the vehicle'stransmission out of park and into drive so that transmission fluidpressure is sufficient to engage transmission gears and transfer enginetorque to vehicle wheels. If the vehicle is equipped with one or moresensors that detect vehicle motion, the engine may be restarted inresponse to motion of another vehicle being detected. Further, if thevehicle receives data indicating that a vehicle in the present vehicle'spath of travel is moving or a traffic signal has changed state, theengine may be restarted in response to motion of another vehicle beingdetected or the change in traffic signal state. In still other examples,the engine may be automatically restarted in response to applying thebrake pedal while the transmission is engaged in park.

Thus, the method of FIGS. 5-8 provide for a vehicle operating method,comprising: automatically stopping an engine via a controller withoutreceiving specific input from a driver via a dedicated engine start/stopinput; and automatically starting the engine via the controller inresponse to applying a brake pedal while the engine is automaticallystopped and a transmission is engaged in park. The method includes wherethe brake pedal is applied via a driver when the transmission is engagedin park, and further comprising determining that the brake pedal isapplied via the controller. The method includes where the engine isautomatically stopped while the transmission is engaged in drive. Themethod includes where the engine is automatically stopped while thetransmission is in neutral.

In some examples, the method further comprises receiving an indicationto the controller that the brake pedal is released after automaticallystopping the engine and before automatically starting the engine. Themethod includes where the engine is automatically stopped while thetransmission is engaged in park, and where all gear clutches of thetransmission are fully released when the transmission is engaged inpark. The method includes where automatically stopping the engineincludes stopping the engine while the brake pedal is not applied andthe transmission is engaged in park. The method includes whereautomatically stopping the engine includes stopping the engine while thebrake pedal is applied and the transmission is engaged in park. Themethod further comprises receiving an indication to the controller thatthe brake pedal is released after automatically stopping the engine andbefore automatically starting the engine.

The method of FIGS. 5-8 also provides for a vehicle operating method,comprising: automatically stopping an engine via a controller withoutreceiving specific input from a driver via a dedicated engine start/stopinput; and automatically starting the engine via the controller inresponse to a brake pedal being applied for more than a threshold amountof time, and without the brake pedal having been at least partiallyreleased, while the engine is automatically stopped and a transmissionis engaged in park. The method includes where the engine isautomatically restarted while the brake pedal is applied. The methodincludes where all gear clutches of the transmission are fully releasedwhen the transmission is engaged in park.

Note that the example control and estimation routines included hereincan be used with various engine and/or vehicle system configurations.The control methods and routines disclosed herein may be stored asexecutable instructions in non-transitory memory and may be carried outby the control system including the controller in combination with thevarious sensors, actuators, and other engine hardware. The specificroutines described herein may represent one or more of any number ofprocessing strategies such as event-driven, interrupt-driven,multi-tasking, multi-threading, and the like. As such, various actions,operations, and/or functions illustrated may be performed in thesequence illustrated, in parallel, or in some cases omitted. Likewise,the order of processing is not necessarily required to achieve thefeatures and advantages of the example embodiments described herein, butis provided for ease of illustration and description. One or more of theillustrated actions, operations and/or functions may be repeatedlyperformed depending on the particular strategy being used. Further, atleast a portion of the described actions, operations and/or functionsmay graphically represent code to be programmed into non-transitorymemory of the computer readable storage medium in the control system.The control actions may also transform the operating state of one ormore sensors or actuators in the physical world when the describedactions are carried out by executing the instructions in a systemincluding the various engine hardware components in combination with oneor more controllers.

This concludes the description. The reading of it by those skilled inthe art would bring to mind many alterations and modifications withoutdeparting from the spirit and the scope of the description. For example,I3, I4, I5, V6, V8, V10, and V12 engines operating in natural gas,gasoline, diesel, or alternative fuel configurations could use thepresent description to advantage.

The invention claimed is:
 1. A vehicle operating method, comprising:automatically stopping an engine via a controller without receivingspecific input from a driver via a dedicated engine start/stop input;and automatically starting the engine via the controller in response toapplying a brake pedal while the engine is automatically stopped and atransmission is engaged in park.
 2. The method of claim 1, where thebrake pedal is applied via the driver when the transmission is engagedin park, and further comprising determining that the brake pedal isapplied via the controller.
 3. The method of claim 1, where the engineis automatically stopped while the transmission is engaged in drive. 4.The method of claim 1, where the engine is automatically stopped whilethe transmission is in neutral.
 5. The method of claim 4, furthercomprising receiving an indication at the controller that the brakepedal is released after automatically stopping the engine and beforeautomatically starting the engine in response to applying the brakepedal.
 6. The method of claim 1, where the engine is automaticallystopped while the transmission is engaged in park, and where all gearclutches of the transmission are fully released when the transmission isengaged in park.
 7. The method of claim 1, where automatically stoppingthe engine includes stopping the engine while the brake pedal is notapplied and the transmission is engaged in park.
 8. The method of claim1, where automatically stopping the engine includes stopping the enginewhile the brake pedal is applied and the transmission is engaged inpark.
 9. The method of claim 8, further comprising receiving anindication at the controller that the brake pedal is released afterautomatically stopping the engine and before automatically starting theengine in response to applying the brake pedal.
 10. A vehicle operatingmethod, comprising: automatically stopping an engine via a controllerwithout receiving specific input from a driver via a dedicated enginestart/stop input; and automatically starting the engine via thecontroller in response to a brake pedal being applied for more than athreshold amount of time, and without the brake pedal having been atleast partially released, while the engine is automatically stopped anda transmission is engaged in park.
 11. The method of claim 10, where theengine is automatically restarted while the brake pedal is applied. 12.The method of claim 10, where all gear clutches of the transmission arefully released when the transmission is engaged in park.